The expandable sealants, which are used in automobiles to fill gaps and voids as well as improve the acoustical properties, have certain inherent problems. These materials at present must be applied at ambient temperatures so as not to prematurely cure or expand the sealant. In this condition, the sealant does not easily flow and is therefore contoured to a specific configuration prior to its application to the automobile. This results in certain instances, in a requirement that as many as twenty-two different sealant configurations must be formed and inventoried for one particular vehicle.
Another drawback to these "cold applied" sealants is that they do not adhere sufficiently to the vehicle and periodically are knocked off or moved from their original location by subsequent cleansing and priming tanks through which the vehicle must pass prior to the sealant being expanded and cured thereby securely positioning it in place. This results in contamination of the cleansing tanks and processes as well as an inferior automobile.
One attempt to overcome these drawbacks might be to apply the sealant hot. Such a hot applied pumpable sealant must not begin to cross link or blow at the temperatures at which the material is pumped as this will create problems in the pump as well as difficulty controlling the quality of the final sealant.
Therefore, what is needed in the art is an expandable sealant which is easily applied, will not be affected by the cleaning or painting processes, and does not activate prematurely at application temperatures.